I have a chance to get a sbc 400 for $200 but it has already been bored out .030 over. If this block needs to be bored out to .040 or .060 over will it cause more of a cooling problem? I know that these things run too warm already and steam holes have to be drilled in the heads. A friend advised against getting the 400 since it's already been bored. If it was a virgin block I'd definitely get it.

I plan to build a 406 or bigger with 11:1 compression and using forged pistons and good rod bolts for a 200 hp shot of juice.

 

unless it's the only block you can find i'd pass on it. if you really have to have it you might want to consider sleeves.

 

It's the whole engine with stock heads and everything for $200. I plan to only use the block and the crank though. It's just hard to find a 400 around here anymore. All the dirt track racers have gone to all the salvage yards and bought them up.

 

You may not actually need to bore this motor at all.
If you're really planning on 11:1 cr . 200hp NOS shot, forged pistons then you'll need increased piston to bore clearance.
And increased ring end gap.
The bores may clean up nicely with just a good honeing.
Trust me you'll want it set up a little "loose" for your planed
Juiced set up. You almost can't get "too loose" here.

Check into the available over bore sizes available for the pistons u plan to use. Many 400 pistons are only available in +.030"

400's suffer cooling problems mostly because of old crusty bad radiators.
A 400 sb is a big motor and needs a NEW "Big Block" radiator
to keep it cool.

 

Good point F-bird'88! I have also been looking at the 391 stroker kits. I already have the block for that and the price isn't a whole lot higher than 383's. I'm still leaning toward the 406 though. Thanks for the replies.

 

Don't bore a 400 block more than .040, the walls are too thin for 0.060.

Use forged pistons and 5.7 rods...the is way better than using the stock rods.

After having my 406 in a few different cars and having friends with them, the overheating problems are:

1. A poor rest of the cooling system

2. Being a moron and not having steam holes drilled in the heads

3. Having 400 heads and running a 350 head gasket

HTH,